Pentazocine Stats & Data
CC(C)=CCN1CCC2(C)C(C)C1Cc1ccc(O)cc12VOKSWYLNZZRQPF-GDIGMMSISA-NPharmacology
DrugBankDescription
The first mixed agonist-antagonist analgesic to be marketed. It is an agonist at the kappa and sigma opioid receptors and has a weak antagonist action at the mu receptor. (From AMA Drug Evaluations Annual, 1991, p97)
Mechanism of Action
The preponderance of evidence suggests that pentazocine antagonizes the opioid effects by competing for the same receptor sites, especially the opioid mu receptor.
Pharmacodynamics
Pentazocine is a potent analgesic which when administered orally in a 50 mg dose appears equivalent in analgesic effect to 60 mg (1 grain) of codeine. Onset of significant analgesia usually occurs between 15 and 30 minutes after oral administration, and duration of action is usually three hours or longer. Onset and duration of action and the degree of pain relief are related both to dose and the severity of pretreatment pain. Pentazocine weakly antagonizes the analgesic effects of morphine and meperidine; in addition, it produces incomplete reversal of cardiovascular, respiratory, and behavioral depression induced by morphine and meperidine. Pentazocine has about 1/50 the antagonistic activity of nalorphine. It also has sedative activity.
Absorption
Well absorbed from the gastro-intestinal tract.
Indication
For the relief of moderate to severe pain.
Toxicity
PubChemThe preponderance of evidence suggests that pentazocine antagonizes the opioid effects by competing for the same receptor sites, especially the opioid mu receptor.
Carcinogenicity
No indication of carcinogenicity to humans (not listed by IARC).
Health effects (PubChem excerpts)
Medical problems can include congested lungs, liver disease, tetanus, cardiovascular effects, infection of the heart valves, skin abscesses, anemia and pneumonia. Death can occur from overdose.
Tolerance & Pharmacokinetics
drugs.wikiNo tolerance chart. Our decay curves for opioids were estimates, and a curve can make tolerance look longer-lasting than it is, which is the dangerous direction.
Opioid tolerance drops fast when you stop, and even a few days off can be enough, so a dose that used to be normal can now stop your breathing. Overdose deaths rise sharply after prison, detox or leaving treatment, and tolerance also falls during a hospital stay. After any break, start with a much smaller amount, try a test dose first, don't use alone, and keep naloxone within reach. Alcohol, benzodiazepines, gabapentinoids and other sedatives make an opioid overdose much more likely.
Sources: FRANK: heroin · National Harm Reduction Coalition · WHO: opioid overdose · Merrall et al. 2010 · Binswanger et al. 2007 · Strang et al. 2003 · FDA 2019: gabapentinoids and breathing
Experience Report Analysis
ErowidDemographics
Gender Distribution
Too few reports for a chart: gender is known from 3 reports, and a split is drawn only from 20 reports or more. Counts are shown instead. Why 20?
- Male 2 of 3
- Not Specified 1 of 3
Age Distribution
Reports Over Time
Form / Preparation
Most common forms and preparations, as a share of the 3 reports that give one
Too few reports for bars: these forms come from 3 reports, and a bar is drawn only from 20 reports or more. With fewer, a percentage cannot tell a common effect from a rare one. Counts are shown instead. Why 20?
- Pill / Tablet 2 of 3
Opioid Equivalence (MME)
NIH HEAL 2024 & CDC 2022Pentazocine 27 mg oral ≈ 10 mg Morphine oral